As one method for decorating pottery, it is known to use a transfer paper which is printed with a decorating ink layer containing a color pigment for pottery on a base paper, which is coated by a size such as dextrin solution and dried, and on which a cover coat layer is printed. This method is the so called "slide" transfer method by water, and comprises separating an integrated cover coat layer and decorating ink layer from a base paper in water, bringing the decorating ink layer into contact with pottery to mount it on the surface thereof and drying, and then, baking the cover coat layer, ink and binder at a high temperature to effect decorating.
A squeegee oil or a cover coat agent of a printed transfer paper for decorating pottery now employed is mainly a solvent type polymethacrylate ester type resin, which has many problems that to be solved and provides a severe problem in ceramic industry.
That is, such printed transfer paper has following many defects:
(1) A solvent type squeegee oil or a solvent type cover coat resin generally contains a solvent having a high boiling point such as toluene, xylene, dimethybenzene, ethylbenzene, triethylbenzene, trimethylbenzene ethylene glycol monobutyl ether, ethylene glycol monoethyl acetate, to prevent clogging in a screen printing plate, and hence, it produces a low drying velocity and a less improved productivity rate. PA1 (2) It produces substantial environmental pollution in the workroom as well as air pollution as a result of the solvent used in the solvent type resin. This defect should be solved quickly because of safety and sanitary conditions and working and environmental disruption. PA1 (3) It takes a very long time for printing using a conventional solvent type squeegee oil, particularly, in multicolor printing because of the low drying velocity of the oil. PA1 (4) Clogging of a screen plate often results because of using of a solvent type resin and, therefore, it is difficult to obtain a fine design. PA1 (5) A conventional solvent type resin for a cover coat readily produces a blocking of printed transfer paper by residual solvent because of its low drying velocity. PA1 (6) Therefore, each conventional printed transfer paper for decorating pottery has to be sandwiched by paraffin papers or the like to prevent blocking. PA1 (7) A conventional printed transfer paper for decorating pottery which employs a solvent type resin for a cover coat is liable to change with time and it loses flexibility resulting in loss of mounting ability during storage. PA1 (I) a polymer and/or copolymer of a compound having a general formula (A): ##STR1## (wherein, R.sub.1 is hydrogen or methyl; R.sub.2 is hydrogen, or alkyl, cycloalkyl, aralkyl or aryl having 1 to 20 carbon atoms), PA1 (II) a photopolymerizable compound having a general formula (B): ##STR2## (wherein, X is hydrogen or methyl, m is a positive integer of 1 to 3, n represents mole of addition, 4.ltoreq.n.ltoreq.100), PA1 (III) a photopolymerizable compound having a polymerizable double bond(s) in the molecule other than the compound having the general formula (B), and PA1 (IV) a photoinitiator. PA1 (I) of polymer and/or copolymer of compound having the above described general formula (A), PA1 (II) a photopolymerizable compound having the general formula (B), PA1 (III) a photopolymerizable compound having a polymerizable double bond(s) in the molecular other than the compound having the general formula (B), and PA1 (IV) a photoinitiator. PA1 (i) It produces an excellent slide transfer ability onto pottery having a curved surface because of flexibility of a decorating ink layer. PA1 (ii) Because the decorating ink layer is of the ultraviolet curable type, it produces less clogging of the screen printing plate to give a fine and clear design. PA1 (iii) It maintains an excellent mounting ability because of no change of decorating ink layer with time. PA1 (iv) Because the decorating ink layer has no change with time, it can maintain an excellent mounting ability. PA1 (v) The baking can provide a superior decoration in color development because of its excellent baking ability. PA1 (i) It produces an excellent slide transfer ability onto pottery having a curved surface because of flexibility of the cover coat layer. PA1 (ii) Because the cover coat layer is the ultraviolet curable type resin and has substantially no solvent, it does not induce the blocking by a residual solvent. PA1 (iii) Therefore, it is not necessary to spend a labor hour for prevention of the blocking such as by inserting paraffin papers, or the like. PA1 (iv) It maintains an excellent mounting ability because of no change of the cover coat layer with time.
It is well known that, as resins for eliminating these defects of a solvent type resin, so called non-solvent type resins, ultraviolet curable resins have been considered, and various proposals have been made. Therefore, an attempt to apply an ultraviolet curable resin to decorating pottery has been considered and is known.
For example, Japanese Patent Laid Open Publication No. 115390/1982 proposes application of an ultraviolet curable resin to a squeegee oil and a cover coat agent of printed transfer paper for decorating pottery, but such an attempt has not yet been put into in practice. The main reason for this is that the resin has defects in its properties such as (1) no flexibility and less ability to be mounted, (2) high decomposition temperature and unfavorable color developing after baking.
The present inventors have proposed application of an ultraviolet curable resin to a squeegee oil (Japanese Patent Laid Open Publication No. 152993/1982) and also have proposed an application of ultraviolet curable resin to a cover coat layer (Japanese Patent Laid Open Publication No. 142385/1982), and thereafter have intensively studied these possibilities. As a result, it has been found that, although these resins have no defect, particularly, in mounting ability for a slide transfer onto a flat surface such as flat ware and tile, they have insufficient ability for slide transfer onto pottery having a considerably curved surface such as a green tea cup, a coffee cup, a bowl of pottery, a deep dish, a flower vase and a rice bowl, and readily produce a cleavage of a decorating ink layer.